[dugrant153]

strangely enough, neither my DA*50-135 (1.4 years old now) and DA*55 (about 6 months old) have had any sort of failure, slow-down, etc.

In fact, I usually find them to be very reliable lenses and will nail the focus when I thought it wouldn't.

Will keep an eye on both but I still trust them quite a bit.

[Ash]

To date, 13/60 responders with SDM lenses report obvious problems. I'm pretty certain this is a result of responders' bias but is still concerning...

[Andrew Faires]

I have used the 16-50 (the worst offender) since 2007 and have likely run 20000 exposures with that lens. To date, there's been no problems at all. I've had the 50-135mm lens since the middle of last year and have probably used it for about 2000 images to date and there's been no issues with that one either.

[Ed n Georgia]

I may be a sucker for punishment. I just purchased a new
DA 17-70 f/4 SDM from B & H. I had a DA* 16-50 for a while and it had no issues with either SDM or de-centering. I hope I have the same results with the DA 17-70.

I'm sure that I'll know soon enough.

[philbaum]

...don't seem to have any problems reported.

PentaxPoke referred me to this poll:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/83743-superson...s-failure.html

So i go there and these 3 lenses have NO reports of problems:

DA-300
DA-200
DA-55

And this lens has only 1 problem reported:

DA 60-250

Geez, if i go to the DSLR forum, i will find the occasional problem reported with a K7, or K20 , or Kx, etc. I don't see anyone suggesting we buy NO pentax cameras.

I understand there are some very angry folks who have owned some SDM lenses. Reading some of their reports, i'd be very angry too.

But do we want to blacklist all SDM lenses because of problems with some lines???

Even one of the "bad boys", the 50-135 has 10 reported problems and 56 no problems. Because of the tendency of customers to report bad news vice good news, we know that the percentage rate of problems is less than 10, how much, neither PentaxPoke, myself or anyone else knows except some pentax staff, and they don't seem to be talking.

Pentax Corp has handled this problem really badly, of course. Are there SDM issues? Of course.

Should we punish Pentax by encouraging an embargo over not buying any SDM lenses? I think thats going too far.

Would i buy the 16-50? No, but i could use something in that range that's an F2.8.

Am i going to sell my DA300. No, its been a real trooper for me over the last year

Am i going to sell my DA50-135? No, its taken too many good pics for me. Looks like i was lucky with a good copy - optics are awesome.

I don't know what the answer is - generally - i'm very anti-corporation when it comes to American corporations - don't get me started :-)

But actively encouraging noone to buy any SDM lenses, even the ones with no or very few problems, seems to be excessive.

PentaxPoke was surprised that i hadn't read any recent SDM threads until this one. Frankly, after i read 2 threads where the problem was eventually determined to be dirty contacts - i lost most of my interest in this "feeding frenzy".

Again, there are SDM problems out there. I'm not saying there aren't.

Phil

[PentaxPoke]

Phil,

You are correct in that the SDM problems on the 16-50, 50-135, etc. have tarnished the other lenses which may not be having any problems whatsoever. Please understand that there are a few of us that are quite angry with our experience with DA* lenses, so we may seem more sensitive than we would otherwise. For that I apologize.

Just a quick recap of my experience with DA*: (please note that I am an engineer, and am very careful with my mechanical devices, so I don't believe any of this is due to mishandling. I have never before had a problem with any Pentax lens. Only DA*. When I trade in my gear, I always have gotten a 10/10 on condition. I have also been a Pentaxian since the early 1980's. I am not a photography novice)

DA* 16-50 #1: Decentered lens, and started showing signs of SDM disease.*
DA* 16-50 #2: Decentered lens
DA* 16-50 #3: So badly decentered that when I posted pictures here on this forum, one of our members said it "made him physically ill."

Three strikes and you're out. I got a full refund on the DA* 16-50, never to go back again.

DA* 50-135 #1: After almost 1 year, it started showing SDM disease. After not being used for a day or two, one would have to "wake it up" by turning the focus ring etc. etc. (no, it is not dirty contacts) Eventually SDM completely failed.
DA* 50-135 #2: Pentax service sent me back a brand new one with a full 1 year warranty (I have never complained about Pentax service). Seemed fine when I got it, and it worked well for a while. Then on the night of my daughters recital, it started to "SDM" again. Took me several minutes to "wake it up." (Missed some important shots in the meantime). After that it worked fine, until the next day when the process had to be repeated. This time, I didn't wait for the slow lingering death. I sent it back in right away.
DA* 50-135 #3 Sold. Never again will I go back to SDM.

The lack of confidence I have with SDM is not only because of my experience, but because Pentax has decided to go the cheap route and use ultrasonic micromotors instead of ring-motors. Canon uses micromotors in only their cheapest lenses. Pentax now uses them in their "pro-level" lenses that cost as much as Canon "L" glass that use ring-USM! I am therefore very suspect about using any SDM product.

Peter's thread was the absolute last straw for me. A pro photographer who has been having similar problems to what I have been through. I have been a Pentax defender for so long, but it is getting difficult. I don't want to think about my gear anymore, and whether or not it will work when I need it. I want to take it out of my bag and get out of my way. I finally decided to downsize my Pentax gear to a minimum while I can still get the value out.

Sorry if I sound bitter, but hopefully you will understand.

(* SDM disease -> "Sometimes Doesn't Move")

[Pentaxor]

I was one of the few people who was encouraged to try out the DA* lenses and develop an LBA for them later on after more than a month of contemplating, initially I'm a prime lens guy and still is in most ways. I was so happy and excited in having one and Pentax gladly obliged by giving me 5 DA* with issues. rest assured that there are no dirty contacts involved. just imagine what a person new to Pentax who have a high expectation in a new sytem would feel if his shift or investment is only worth a year of reliability or otherwise unreliable. lucky for Pentax it got it primes to keep them afloat. the two DA* zooms are nothing more than doing a harakiri.

[Blue]

I just traded up from my 55-300 to the Da* 300mm. Due to these reports on SDM, I got an extended warranty.

[brecklundin]

had a 50-135 it lasted less than three weeks...then I learned of the whole SDM fragility issue that happens in enough copies to put me completely off SDM until, at the soonest, HoyaTax finally offers up a true ring-type AF system. My bet as to why we have not seen a new version of SDM in ANY lense is because of the existing inventory cached around the globe and HoyaTax is not willing to simply blow the more problematic lenses out before releasing new models with a real ring-AF system that is as robust as the weather sealing an build quality. Until then, I am not going to buy another SDM lens...one was enough, not because it failed as that happens for all mfg's but because when mine began to show signs of failing so soon, I of course, researched to find out not only that this issue is the same in most reported failures but the failures almost always occur in the 13-18 month period right after the warranty runs out. The other reason is how long Pentax has taken to get a lense repaired, to the point of claiming to send the copy back to Japan. Gimme a break, just give the customer the option of a properly adjusted refurnished or even hand checked copy rather than the wait as that can take months fer goodness sakes.

Not even Sigma is so cavalier with warranty repair or even post warranty repair. In fact once because their NY facility wss backed up, the sent my copy to CRIS in AZ to make sure it was done soon as possible. They once even overnighted a lens I had just sent in for a cleaning and adjustments/calibration after a longish camping trip. On top of it they did not charge me a dime even though the warranty was at least a year expired. THAT is how to treat people who drop a grand on a lense multiple times.

I know some people have reported that service seems to at least be trying to improve but I want more proof as people comment on good service and support. In the mean time I am done with SDM.

[Class A]

To date, 13/60 responders with SDM lenses report obvious problems. I'm pretty certain this is a result of responders' bias but is still concerning...

Why should it be concerning?

A lot more than just 60 SDM lenses were sold and I don't think anyone here believes that the 13 problem-responses would scale up accordingly.

I've written before that I don't have the answers but it seems unlikely that there is an SDM problem which is considerably bigger than camera problems or other QC problems like decentering.

It is anyone's choice whether they want to add another source of potential failure when the screw drive isn't really slower.

I have a deal for Pentax: They could add optional screw drive support to be enabled in-camera for SDM lenses on the basis that this may use less battery power. So they could give users the choice without making an implicit admission that SDM isn't entirely reliable, whether the later would be warranted or not.

Not even Sigma

???
As if Sigma were a second class manufacturer. Look at their EX glass and compare it to similarly priced Pentax glass. From build quality, finish, optical performance, number of blades, and things like smooth aperture shapes even at wider apertures for the models I compared, Sigma always came out better.

Sigma may have had a shoddy past, but it seems that reputation sticks longer than it should.

[Ash]

Why should it be concerning?

A lot more than just 60 SDM lenses were sold and I don't think anyone here believes that the 13 problem-responses would scale up accordingly.

I've written before that I don't have the answers but it seems unlikely that there is an SDM problem which is considerably bigger than camera problems or other QC problems like decentering.

All based on the proportion. The 20 odd percent is not a favourable figure.
Low sample size, fine.
How about absolute numbers rather than relative ones then...
I'm not sure I believe Pentax saying that repair numbers are exceeded by return numbers for SDM lenses. This doesn't take into account those who've had their lenses beyond the measly 1yr warranty period, crap out and tossed in preference of a screwdrive lens or even switch of system...

I have a deal for Pentax: They could add optional screw drive support to be enabled in-camera for SDM lenses on the basis that this may use less battery power. So they could give users the choice without making an implicit admission that SDM isn't entirely reliable, whether the later would be warranted or not.

That may well happen, but it's also possible that they'll abandon the dual focusing system altogether in their DA*s and just stick with SDM. After all, if the SDM fails in the 16-50 or 50-135, the screwdrive doesn't kick in as a backup...

???
As if Sigma were a second class manufacturer. Look at their EX glass and compare it to similarly priced Pentax glass. From build quality, finish, optical performance, number of blades, and things like smooth aperture shapes even at wider apertures for the models I compared, Sigma always came out better.

Sigma may have had a shoddy past, but it seems that reputation sticks longer than it should.

Well that's where I'll agree to disagree with you. My Pentax and Tamron glass has outdone all my previous Sigmas of similar calibre (and I have had quite a few) in their results.

I've handled most of their 'good' lenses (modern versions), EX and non-EX (not the big guns like the 120-400 yet though) and have just not been impressed by their optical quality where it counts (i.e. larger than f/8). The 70-200 HSM is a prime example - I wish I got a hold of the older non-HSM version though - that one's much more impressive.

[Class A]

Low sample size, fine.

Low sample size is one problem. The much bigger problem is that the sample is very likely skewed.

Well that's where I'll agree to disagree with you. My Pentax and Tamron glass has outdone all my previous Sigmas of similar calibre (and I have had quite a few) in their results.

Let's agree to disagree, but let me add that we were probably looking at different lens models to form our opinion. I'm impressed by the Sigma 70/2.8 macro which PopPhoto calls "faultless". Imageressource use that lens as a benchmark lens to compare camera bodies across different brands. I'm also impressed by the Sigma 28/1.8 with its very useful bokeh and nine aperture blades that always form a roundish shape, unlike the FA 50/1.4 that gives you jaggies below f/2.8 or similar. Sigma also makes less than stellar lenses, as Pentax does, so it probably is a matter which ones you compare with each other.

... have just not been impressed by their optical quality where it counts (i.e. larger than f/8). The 70-200 HSM is a prime example.

From dpreview: "The optics are perfectly competent, if not outstanding". Maybe it's less then stellar close focusing qualities have failed to impress you but unless your copy was a dud, it should have been great in applications other than close focusing. Also it seems that this lens is built to a price and shouldn't be compared to similar specified but higher priced competitors without allowing for some compromises.

[Ash]

Points taken Class A.
I might just be warped from my ordinary experiences from Sigma lenses.
Close focusing deficiency was not the only gripe I had with their new 70-200.
But I am yet to try their 70 macro...

[WerTicus]

seems like pentax use underpowered electric motors in their sdm lenses, hence the failures and lack of speed.

electric motors are bullet proof unless they are being pushed too hard constantly.

[cupic]

HSM does work faster and harder so eventually it will suffer,I usually split the function with a mixture of MF(I know the purpose of this lens is quick focus)but for those times when not critical MF is better

cheers